Train control



May 11. 1926..

W. K. HOWE TRAIN CONTROL Filed Oct. 21, 1922 VENTOR f. ff mza jiTToRNEY5 I Eh.

Patented May 11, 192%.

wmrnnor K. now-n; or ROCHESTER, new assreii'cn-rouennnnan RAILWAY SIGNALCGMIEANY, 0F GATES NEw 'i" TRAIN CONTROL;

Application filed. Gotober 2-1, 1922. $eria1 No. 596,075.

This invention relates to automatictrain speed control systems forrailroads.

Broadly considered, this invention contemplatesthe provision ofautomatic equipment on the trackway and on a train for enforcingpredetermined speed limitations, which the train can not exceed.xvithout an automatic brake application, at various points in thetravel ot the train, such as in a .cautionblock, it being moreparticularly desired to provide anequipment of this character which Willpermit any desiredspeed limitv to beset up a-t any desired point asrequired by a simple adaptation of the trackivay equipment. Morespecifically, the invention involves the use of pairs of influencedevices on the tr ack'l'ocated at the appropriate control points, thespacing or distance apart of the elements of each'pair dete mining thelimiting speed for trains at that location. Inasmuch as tratiicconditions ahead of a train in a block may change at any time While thetrain is in thatblock, it is considered desirableto make provisions toautomatically remove the limitations inrposed uponthe movement of thetrain by a pair. of track devices at the next pair of track devicesencountered by the train, set ting upit necessary at the second pair anew restriction upon the movement of the train. Inother Words, it isthought to be important in speed control systems of the typeimposingspeed limitations from point to point to governthe trainstep-by-step, S0 to speak, from point to po nt, so that the train may bereleased from the dominance of the automatic system at each controlpoint.

To carry out this principle or idea of step-by-step control aboveindicated, it is proposed in accordance with this invention to make thefirst track element of each pair permanently etl ective to influence theapparatus on a passing car. to construct the carcarried apparatus sothat it Will be automatically restored to normal by such permanentlyactive track element, and to make the speed restrictions automaticallyenforced at each pair of track elements dependent notonly On traflicconditions but also upon the spacing of the particular pair of elements,so that any'desired speed limit may be set up at any selected point byseparating or spacingthe elements of a pair accordingly.

In one specific embodiment of the invention herein disclosed, thedesired speed limits at the respective control pointsareentorced inaccordance wth the time-distance interval principle, that is, thecarapparatus acts'to automatically apply the brakes at each pair oftrack elements it the car traverses the space between this pair ofelements in'less than a PTBClQtBTHllHQd interval of time measured by atime-controlled or time-element device on the car. In this type of:system, it an automatic brake application is produced at a'pair of trackelenients'due to excessive speed at that point, it is desirable to.permit the release of the brakes at the next pair 'ot track elements,either because the-engineer has been particularly diligent in stoppingthe train, or because traffic conditions ahead in the meantime havecleared upand make further action ot the brakes unnecessary. Thisdesired end isaccomplished according to the specific embodiment of theinvention disclosed by automatically restoring the brake-setting orcontrol means: at the 'i'irst track element of each pair, permitting theengineer to release the brakes, unless the speed of the train at thissucceeding pair is too high for safety and traffic conditionsfin advancestill require continued'reduction in speed.

Various other characteristic features of the invention, its advantages,and adaptabilities to practical operating"conditions will be pointed outhereinafter as thedescription 01 one specific embodiment thereofprogrosses.

In the accompanying -draWing,.Figure l is a diagrammatic view showingthe trackvvay devices and circuits according to this invention Fig. 2illustrates in a simplified and con ventional manner carcarried devicesand circuits of this invention, and also a pair of track elements orinductors to illustrate their cooperation with the carv apparatus; and

Fig. 3 is an. enlarged sectional view of the clutch F shown inFig. 2. I

In the embodiment of the invention illustrated, the transmission of thedesired control influences to limit the speed at several points in ablock is produced by track elements which are governed in accordancewith traiiic conditions ahead. Various arrangements of trackivaycircuits suitable for the purpose of. controlling these track elementsmay beemployed, and it should be understood that the arrangement shownin Fig. 1 is only a typical example. Referring to Figure 1, the trackrails 1 of the railroad track are divided by insulated joints 2 intoblocks in the usual way, on block I with the adjacent ends of two otherblocks H and J being shown. The parts and circuits associated with thevarious blocks are the same, and for convenience will be given likereference characters with distinctive exponents.

Each of the blocks is provided with a track battery 3 and a track relay4, the same as in ordinary block signal systems. This invention ispreferably used in connection with the ordinary block signals, either ofthetwo or three-position semaphore type, position light signals,distinctive aspect color-light signals, or the like. For conveniencefined semaphore signals Z have been shown conventionally withoutattempting to illustrate their well-known control circuits and devices.

In each block are provided pairs of track elements T and t at theseveral points in the block at which the speed of the. train is to bechecked. the spacing between the elements T and t of each )airdetermining the distance a train is permitted to run in a predeterminedtime at this point in the block. In the specific embodiment illustrated,these track elements are shown on the right side of the track whenfacing in the normal direction of trailic, as indicated by the arrow.Each of these track elements T and t com-- prises a U-shaped iron core 5terminating in enlarged pole pieces 6, the back yoke of the core 5 ofthe track element It being provided with a coil 7. The cores 5 arepreferably made of a good quality of laminated sheet iron, similar tothat used in transformer construction, in order to reduce the eddycurrent loss, produced by a change of flux through the core, to aminimum. At each point of location of a pair of track elements T and tis located a repeater track or line relay 8, these relays 8 beingconnected in multiple between the line wire 9 and a common return wire C(not shown), and are energized when the track relay l of the block inadvance is energized.

The energizing circuit for the repeater track relays 8 of the block Imay be traced as follows:beginning at the terminal B of a suitablesource of energy such a battery, wire 10, front contact 11 of the trackrelay line wire 9, lead-in wire 12 to each of the repeater track relays8, lead-out wire 13 leading from each relay back to the common returnwire C connected to the other terminal of this source of current.

From this circuit it is apparent that when the track relay of the blockin advance is energized that each of the repeater track relays 8 willlikewise be energized, thus closing their front contacts 14. .Thesefront contacts 14 when closed close the coil 7 of each of the respectivetrack elements it in a circuit'preferably of low resistance, therebycausing them to function in a manner as will be explained hereinafter.The track apparatus at each control point in a block is the same, exceptfor the spacing between the elements of each pair, and for conveniencethese pairs of elements have been designated with the same referencecharacter having distinctive alphabetical exponents.

The car-carried apparatus of one specific embodiment of this inventionhas been illusrated in Fig. 2, and comprises suitable devices which willfirst be separately de scribed. One of these devices comprisesaninfluence receiving car element- L consisting of a ll-sh-aped core 15,preferably constructed of laminated transformer iron, and terminating inenlarged pole pieces 16. The leading leg of the U-shaped core of the carelement L is provided with a primary coil P, whereas the other leg isprovided with a secondary coil S. These car elements L are preferablymounted directly on the truck of the railway vehic e, and are protectedfrom excessive jars and vibration, and from the weather in any suitablemanner. The specific construction of the mounting of this car element Lis not within the scope of the present invention, and therefore has notbee illustrated in detail.

The car-carried apparatus includes a control relay CR, a repeater relayRR and a check relay CK. Although these relays have been shownsubstantially identical, this illustration is merely conventional, andin practice the control relay CR will be constructed to be moresensitive and will be provided with much smaller movin parts and contacts than the other relays, and will therefore function on a smallerchange of energy. The repeater relay ER is preferably of a slow actingtype, and has been shown cenventionally as a retarded relay. This relayRE is also provided with special contacts for controlling severalcircuits in a manner so that at least one of these circuits will beclosed at the relay at all times, which will for convenience be referredto as a maltebeforebreak contact hereinafter. Each of these relays havetheir moving parts well balanced so that they will not be affected bvjars and vibration, and are preferably mounted in a comparatively heavyspring supported relay casing, whereby the ars and vibration will to acertain extent be absorbed and transformed before reaching the relays.thereby minimizing their effect to produce improper operation of theserelays.

The car-carried apparatus also includes a train control device K whichhas been illustrated as an electro-pneumatic valve. This train controldevice may control the train in any suitable manner as, for instance, byaclSO Losses? tuating the usual engineers valve in a manpipe to apredetermined extent only, for rea-.

sons well known to those skilled in the art, and is also preferablyconstructed so that if automatically actuated to its normal conditionthe brakes will not be automatically released, but will merely permitthe engineer to again release the brakes. This latter feature isdesirable because if the engineer should be disabled, asleep or notattending to his duties for some other reason, a single automaticactuation of the train control device K will assure stoppage of thetrain. This train control device K is of the normally energized type,and has its normally energized circuit completed through the contacts 1Scontrolled by the armature of its electro-magnet. lherefore, a momentarydeenergization of the train control device K will permanently deenergizeit, because its energizing circuit will be interrupted permanently byits front contact 18.

Another element of the car-carried apparatus embodying this inventioncomprises a time element or time'controlled device TC. This timecontrolled device TC is provided to normally close an auxiliary circuit,to open this circuit a very short period after the device has beeninitiated, to maintain this circuit open for a predetermined time, andthen again close said circuit. This time element device TC may take anyone of a variety of forms, and may employ. any one of the well-knownprinciples for measuring time. For instance, it may ineludewellknownclock mechanism, or it may be constructed to measure an interval of timeby the escape of fluid through an orifice, or the like. For convenience,this time controlled device TC has been illustrated as a mechanismoperated by a motor M, which is pref.- erably of the type that willmaintain a con? stant speed irrespective of a slight variation in thevoltage of the source of E. M. F. illustrated as a battery 20. Thismotor M is pro-. vided with an armature having a commutafor 21cooperating with brushes 22, and having a field winding 23 preferablyconnected in multiple with the armature 21, this field winding andarmature being connected across the battery 20. The constant speedoperating characteristic of this motor may 3e obtained to a large extentby proper design, and if desired, a suitable speed controlling regulatormay be incorporated therewith to give this motor a constant speedcharacteristic.

The motor M through the shaft 24 drives the housing of a friction clutchF, the other member 19 of said friction clutch being rigidly connectedto a shaft 25 provided with a worm 26, and the housing F and member 19are preferably spring pressed toward each other against an interveningfriction disk, by a spring 17. The construction of this friction clutchis preferably such that a predetermined torque may be transmitted fromthe shaft 2% to 25, but if a higher torque is attempted tobe-transmitted this clutch will slip, the clutch being preferably sodesigned that such slippage thereof will not produce detrimental heatingof the friction surfaces.

The Worm 26 of the shaft 25 is in continuous operative engagement with aworm wheel 27, which has fastened thereto in any suitable manner a disk28 which is provided with a contact sector 29 insulated therefrom byinsulation 30. As the worm wheel 27 and the disk 28 are rotated in thedirection of the arrow by the motor M through the intervening frictionclutch F, this worm wheel and disk will be stopped by the projection 31of the disk'28 coming in' contact with the extension 82 of the armatureA of the time starting or holding magnet GS. With the disk 28 in thisposition, the contact sector 29 will bridge the stationary contacts 33and 84. If new the time starting magnet CS is for any reasondeenergized, the disk 28 will be rotated in the direction of the arrowthrough the action of the friction clutch F until the projection 31 ofthis disk is stopped by the other extension 35 on the armature A. Thearrangement of parts is such that if the projection 31 is stopped by theextension 85, the stationary contacts 33 and 34 will not be bridged bythe contact sector .29.

An auxiliary checking device to check the continual rotation of themotor M is pro- 1 vided. This device is of the Well known centrifugaltype, and comprises a collar 10 rigidly fastened to the shaft 24, acollar 41 slidably mounted on thisshaft and biased from the other collar40 bya spring 42. Two pairs of links 43 are provided to coin nect thesecollars. These links are pivotall-y connected together and haveconnected thereto at the junction of these links cc trifugal weights 4%,whereby the rotation of the shaft 2a causes the weights at to compressthe spring 4-2 and shift the collar 41 along the shaft 24-. The collar4C1 has connected thereto but insulated therefrom a contact disk t5. Ifthe motor is rotating the shaft 2% at or above the predetermined speed,this contact disk to will be in a position to bridge contacts 46 and 17conventionally illustrated by arrows.

A reset switch BS is preferably provided 1 in order to enable theengineer to release the brakes after an automatic brake application hasoccurred, so that he may again proceed, if his train should happen to bestopped'between pairs of track elements.

lit)

In order that the engineerbe unable to reset the automatic train controlapparatus back to its inetlective condition while the train is beingslowed down, this reset switch is preferably n'iounted on the railwayvehicle so that it is only accessible from the ground. As will appearhereinafter, this switch acts to reset the car-carried apparatus back toits inactive condition if this reset switch is momentarily operatedOperatiow-rtssume that a railway vehicle is traveling equipped with thecar-carried apparatus in its normal condition, that is, that thisvehicle is moving between control points in a block when the next blockin advance is clear. Under these conditions, certain of the circuitswill be energized from a suitable source of energy, and in order tosimplify the illustration of these circuits the letter B has been usedto designate one terminal of a suitable source of E. M. F, whereas theletter C has been used to represent a common return wire leading to theother terminal of said source.

The circuit for normally ei'iergizing the control relay CR may be tracedas follows beginning at the terminal B of a suitable source of energy,preferably a battery, wire 50, front contact 51 of the control relay CR,wires 52 and 53, winding of the control relay CR, wire 5 the blade ofthe reset switch RS, wire secondary coil S of the car element L, wire 56back to the common return wire C.

The primary coil P will be energized through a circuit which may betraced as follows :beginning at the terminal B oi": said source of E. M.F., wire 57, winding of the check relay CK, wire 58, primary coil P ofthe car element L, wire 59 back to the common return wire 0.

With the control relay GR in its energized condition, a circuit for therepeater relay will be completed which may be traced as follows:beginning at the terminal B of said source of E. M. F., wire 50, frontcon tact 60 of the control relay CR, wire 61, winding of the repeaterrelay RR, wire 62 back to the common return wire C.

l Vith the repeater relay BB in its energized condition, a circuit forthe time starting magnet GS of the time controlled device TC will becompleted, which may be traced as follows :beginning at the terminal Bof the battery, wire 63, contact 64 of the repeater relay RR, wire 65,winding of the time starting magnet CS, wire 66 back to the commonreturn wire C Another circuit will be closed when the repeater relay ERis energized, which may be traced as follows :beginning at the terminalB of the battery, wire 63, make-before-break contact 67, wire 68, stickcontact 18 of the train control device K, wires 69 and 70, front contact71 of the check relay element L. The magneto-motive-force produced inthe car element L is mainly due to the primary coil P, because thecurrent :tiowing in the secondary coil S is very small, it being onlysufficient to maintain the sensitive control relay CR energized.

lVitha railway vehicle equipped with this car apparatus in its normalcondition, as just described, let us assume the vehicle to pass a trackelement in the active stopping condition, say track element T. As thecar element L passes over the track element T,

the reluctance of the magnetic circuit includ ing the core 15 of the carelement is momentarily reduced. This change in reluctance causes a.sudden increase of flux and then a decrease its normal condition, partlydue to a diversion of flux from leakage paths, and partly due to anincrease in the total flux through the primary coil P. This suddenincrease and decrease of flux through the secondary coil S induces avoltage therein, similar to that of a single cycle of al ternatingcurrent E. M. F. The secondary winding S is so connected with respect tothe battery that the first wave of the unicycle of E. M. F. opposes thevoltage of the battery, thereby reducing the energizing current of thecontrol relay OR to an extent to cause its armature to assume thedeenergized position by the action of the spring? Since the controlrelay CE is connected in a stick circuit, it will be permanentlydeenergized until picked up by some other means.

The deenergization of the control relay CR interrupts the energizingcircuit for the repeater relay RR, thus causing its armature to assumeits deenergized position by the action of the spring 7 6, therebyclosing an auxiliary circuit for the train control de vice K shortlyafter which the main circuit for this train control device K will bebroken, this overlapped circuit closing tea ture of the repeater relayRR being due to the construction of the n'iake-betore-break contact 67and is obvious from the construction of this switch as illustrated.

This auxiliary circuit for the train control device K may be traced astollowszbeginning at the terminal B of a battery, wire 63,make-before-break contact 67, wire 78, stationary contact 38, contactsector 29, stationary contact at of the time control device TC, wire 79,stationary contact l7 contact dish and stationary contact 4.6 of thecentrifugal device, wi cs 80 and 70, front contact 71, of the checkrelay CK, wire 72, winding of the train control device K, wire 73 backto the common return wire G.

fil'inr'iltansously with the energization of the auxiliary circuit anlthe deenergization 01 the main circuit of the train control device hi,the time starting magnet GS of the tine controlled, device TC will bedeenergized, thereby causing the armature A to assume its deenergizedposition and tree the projection 31 from the extension of this armature,thereby allowing the disk 28 to start in rotation in the direction ofthe arrow.

The deenergization of the repeater relay completes a pickup circuit forthe control relay CR, which may be traced as follows: beginning at theterminal B of a battery, wire 63, contact (is of the repeater relay RR,wires 81 and 53, winding oi the control relay CR, wire at, blade of thereset switch RS, wire 55, secondary coil S of the car element- L, wire56 bacl: to the common ,return wire C. The completion of this pickupcircuit causes the control relay OR to pick up and again close its stickcircuit, as heretofore traced. This energization of the control relay CRagain energizes the repeater relay RR, and recloses the main circuit forthe train control device K. The parts are arranged so that this maincircuit is again closed before the disk 28 has rotated far enough tocause the contact sec-- tor 29 to interrupt the circuit completedthereby. it should be noted that the time starting magnet CS has beenagain energized by the contact 6% of the repeater relay RR; and theparts are back in the normal position except that the disk 28 is nowmaking its cycle of rotation in the direction of the arrow, and after apartial revolution has opened another break in the auxiliary circuit ofthe train control device at conta ts 33 and'Sa without any ct fee-t uponthe device K at this time.

It is thus seen that a single inductive influence transmitted from thetrackway merely initiates the cycle of operation of the time elementdevice TC and does not deenergize the train control device K, andinterfere with the operation of the train.

Let us assume now that the train is entering the block I under cleartraliic conditions ahead, and that it has passed by the track element 1which has caused the time con trol device to be started upon its cycleof operation. The passage or the car element L over the track element 25will, however, not

- interfere with the movement of the train because this track element 25is then in its in.- active or ineffective condition, because the coil 7ct this track element is closed in a circuit of low resistance. Thisresult is due to the fact that as the car element L passes over thetract: element 6, only a very small voltage will be induced in thesecondary coil S or this car element. One ground of reasoning my whichthis slight induction of voltage may be accounted for is based on thetheory that a closed winding in a variable flux field will produce ademagnetizing action. over the tracl: element t a change of flux isproduced in this track element which induces a comparatively largecurrent in the. close-circuited coil 7 on the back yoke of this trackelement, this current by well known laws of induction being); in adirection to prevent a further increase of flux through this trackelement. Since this track element 25' to a certain extent prevents afurther increase of flux therethrough, the reluctance of the magneticcircuit including the car'element L will not be materially reduced, andtherefore a very small voltage only will be induced in the secondarycoil S which isinsufiicient to actuate control relay Cl Since the secondtrack element has been shown to be ineffective under clear traliicconditions, only one inductive influence is transmitted at each controlpoint and the train may pass'throug'h a clear block unrestricted in itsmovement.

Let us assume now that the railway vehicle in question is entering theblock 1 minor caution traffic conditions, that is, when the block J isoccupied by another train. The presence of the train in the block Jshunts the track relay al thereby deenergizing it and cutting oil energyfrom the line wire 9, thereby deenergizing each of the repeater trackrelays 8. This deenergization of the track relays 8 opens the circuitfor each of the coils 7 of the track elements If, t and t Let us assumethat the car element L has passed over the track element T, and that thetime control device TC has been initiated upon its cycle of operation.First, suppose the speed is too high and the vehicle will 1 pass by thetrack element t before the predetermined time to be measured by thistime controlled device TC has expired, that is, before the time controldevice TC has returned to its normal position. As the car element Lpasses over the track element 1? with its coil 7 open-circuited,acontrol influence will be transmitted to the control relay CE.- in thesame manner as heretofore explained in connection with the track ele- 1ment T, thereby deenergizing this control relay OR. The deene-rgizationof the con ,trol relay CR deenergizes the repeater relay RR, therebyclosing at its back contact a break in. the auxiliary circuit for thetrain That is, as the car element passes control device K and openingthe main circuit of this train control device. The closure of this breakin the auxiliary circuit for the train control device K at this timedoes nothing toward energizing this train control device, because thiscircuit is open between the stationary contacts 33 and 34. (disk 28 nothavingreached its normal position) and thereforethe train control deviceK will be deenergized, and the brakes Will be applied in a n annerheretofore explained. The. decncrgization of the repeater relay RR willagain pick up the control relay CR through the pickup Wire 81 asheretofore exolained, thereby again causing repeater relay HR to beenergized, Which in turn will again energize the time starting magnet GSof the time controlled device TC, whereby the disk 28 of the timecontrolled device will again be stopped in its normal position. Thetrain control device K remains deenergized because relay ER is picked upand the main energizing circuit for device K is broken at its owncontacts 18.

Second, suppose that the speed of the train is less than that prescribedby the spacing of the track element T and 25. Under these conditions,the disk 28 will have returned to normal position before the secondimpulse is received from the second track element t; and since theauxiliary energizing circuit for the device K is thus closed at contacts33 and 3% at the time the relay RR drops, the device K is kept energizedand the only result is to startthe disk 28 on another cycle ofoperation,

Considering 110W the case Where the brakes are automatically applied atthe pair of track element-s T and t on account out excessive speed, thetrain will. of course be slowed down and if it is possible for the trainto reach a speed at the next pair of elements T and t lower thanprescribed by the spacing of these elements, it is evident that it wouldbe safe and proper to permit the release ot' the brakes. Similarly, theblock J may become unoccupied by the time the train in question, afterpassing the pair of track elements T and t, reaches the pair of trackelements T and t; and in this case also it is safe and proper to permitthe release of the brakes irrespective of the speed 01 the train at thetime. In any event, it is contemplated in this invention to restore thetrain control device K at the next pair of elements, as T and t, andthereafter, it necessary, to cause another opera tion of the device K.

To make clear this automatic restoration of the device K, imagine thetrain, with device K deenergized and the brakes acting, is continuingits travel and passes over the track element T. This Will deenergize thecontrol relay GR in the same manner as hereto- .fore explained inconnection with the track clement T. The deenergization of the controlrelay CR deenergizes the repeater relay RE, which in turn deenergizesthe time starting magnet CS and allows the disk 28 to start upon itscycle of rotation. Before the contact sector 29 breaks the shunt betweenthe stationary contacts 33 and 34;, the auxiliary circuit for the traincontrol device K will be completed by the back portion of themake-before-bieak contact 67 of the repeater relay RR, thus causing thetrain control device K to be energized. The enen gization of the traincontrol device K causes the back contact 18 thereof to close the stickcircuit at this point, and as the repeater relay BB is again energizedfor reasons heretofore explained, the train control device K will beenergized through this stick circuit. It is thus seen that, if the trainis approaching a control point with the train control device Kdeenergized, this device K will again be energized when a single activetrack element is passed over.

Let us assume now that the train is passing from the track element T tothe track element z with the brakes acting because the previous controlpoint Was passed at excessive speed, and that the speed is still higherthan the permissive speed prescribed by the spacing of these elements.Under these conditions, a control influence will be transmittedinductively from the track element t to the control relay CR before thedisk 28 of the time control device TC gets back to its normal position,and therefore the train control device K Will again be deenergized inthe same manner as it did when passing from the track element T to thetrack element 25 in less than the required time, as heretoforedescribed. The energize.- tion of the train control device K occurringat the track element T will, therefore, be only momentary if the speedis still excessive and will not materially affect the airbrake system ofthe train or permit release of the brakes because of the short timeduring which this device K is actually energized.

If it should happen that the block J is clear at the time the trainpasses the track element 25, the device K will not be deenergized, asjust described, because the element 6 will then have its coil 7 includedin a circuit of low resistance and will not cause dropping of relay CR.

If the speed of the train at the elements T and t is lower than thatprescribed by these elements, the device K remains energized, andremembering it is being assumed that a brake application "as made at theelement T and t, the engineer may release the brakes.

It may happen that the train, after an automatic application of thebrakes, csoecially at the elements T and 15", will be F 1 decreasesstopped before it reaches" the first track element of'the next pair, asT, and can not obtain thereat an automatic restoration of the device K.In order that the engineer may again proceed under these circumstances,he Will be required to operate the resetswitch RS which is onlyaccessible from the ground, as heretofore mentioned. The engi'neer IIOWmomentarily breaking the circuit of the control relay CR, by actuatingthis reset switch RS, causes the control relay CR to be dee'nergiz e'd,thereby causing the several devices and the time controlled device TC tobe actuated in the same mannor as if this control relay had beenautomatically actuated by an inductive control influence. Among otherthings restoring the device K and maintaining it energized, because ofthe momentary deenergi'zation of the repeater rfelay Rlhcauses the traincon trol device K to be picked up by the completion ofthe auxiliarycircuit, and it Will then be maintained energized through its stickcircuit similar to th'epicking up of this train control device K whenpassing over the track element T in the ope "ation heretofore described.

The engineer can not carelessly leave the reset switch RS open ormaliciously fasten it open, because the device K will be deenergizedupon so doing, due to the opening of contacts 83 and 34:, the relays CRand RR be ing deenergized.

It is thus seen that, if a car equipped with the apparatus illustratedpasses over two successive active track elements in less than apredetermined time measured by the time controlled device TC, the traincontrol device K will be deenergized. After this device K has been thusdeenerg'ized and the .train passes over a succeeding pair of activetrack elements, first in less than said predetermined time at excessivespeed), thetrain control device K will he only momentarily energized;second, in more than said time (safe speed) the device K is energizedand kept energized. Also, if the second element of said succeeding; pairis in an inactive condition, due to the clearing up of the block ahead,then the device K is energized and kept energized irrespective of thespeed.

T he check relay CK has been provided so that the train control device KWill be deen' ergized when the reduction in the exciting current flowingthrough the primary coil P is beloiv that necessary to produce thenecessary magnetomotive-force for transmitting a control influence tothe control relay CR, either due to a break in this energizing circuit,the depreciation of the battery or other source of current, or the like.The check relay CK is so designed that it will release its front contact71 when the current flowing: therethrough and through the prin'rary coilbelo'u 'the necessaryvalue just referred to, thus dee'nergi'zin-g thetrain control device K and bringing then-aim to a stop:- This checkr'elayCK thus assures the stoppage of the train if there not sufficientmagneto-motive-force in the car element L,

and the engineer ivould be required to oper ate a suitable cut-outdevice (not shown) for cutting out all of the automatic controlapparatus under this condition.

Let us assume that another break in the automatic control apparatustakes place,

namely, the energizing circuit for the time starting magnet GS, eitherdue to a failure to make contact at the front contact 6a of the repeaterrelay ER because the Winding of this relay is shorted, or because thereis a permanent break in this circuit. The deenergization of this timestarting magnet CS will allow the disk 28 to rotate in the direction ofthe arrow until the projection 31 strikes the extension on the armatureA of this time starting magnet. With the disk 28 in this position thecontact sector .29 will not bridge the stationary contacts 33 and 34,and consequently 'When the first control influence is transmitted afterthis break has occurred the-train control device K Will be permanentlydeenergized due to this permanentbreak in the auxiliary energizingci-rcuit for this train control device K. Ob viously, the train controldevice K will be deenergized if the repeater relay RR or the controlrelay CR should fail and be permanently deenergized. It is thus seenthat the failure of any of the'circuits shown in the car-carriedapparatus as Well as along the tnckway function-in a manner so thatcircuit failure will cause an automatic brake application.

Let us assume now that for some reason the motor M discontinues tooperate, either reducing its speed beloiv the predetermined speedheretofore mentioned, or discontinues to operate altogether, either dueto failure of the motor itself or due to the failure of energy foro-peratin-g the same. This de crease in the speed of the shaft 24;causes the spring L2 to shift the collar 41 and con.- tact disk lconnected thereto to the right because of the decrease of centrifugalforce acting: on the Weights i l. This shifting of the disk 45 providesanother break in the auxiliary circuit for the train control device K,so that upon the reception of a control influence thereafter, the traincontrol device K will be aei manently deenergize'd in a similar manner,as explained when this circuit is permanently opened at the contacts 3and 3d.

In order to explain the nature ofj'th-e invention, and the functions andmodes of operation of the means constituting this invention, there hasbeen shown and deribed one typical embodiment "thereof hiclrha's'beeiiselected-moment a new of facilitating explanation of the invention, thanfor the purpose of disclosing the specific structure and arrangement ofparts and circuits preferably employed in practice; and it should beunderstood that various adaptations, modifications and additions may bemade to this particular disclosure without departing trom the invention.For example, it is contemplated that the system may be used inconjunction with any suitable or well-known type of block signal system,either of the direct or alter nating current type, and that variousforms of mechanism for controlling the application of the brakes and thesupply of propelling power may be used and governed the same way as thetrain control device K, such control mechanism being of course designedto efi'ect an automatic brake application that can not be forestalled orprevented by the engineer, and in a manner conforming with recognizedair brake practice.

Other deviations from the specific disclosure will be evident to thoseskilled in the art, and it should be understood that the specificstructure shown and described is merely illustrative of the invention,and does not exhaust the various embodiments thereof.

What is desired to be secured by Letters Patent of the United States, is

1. In a train control system, the co1nbination of car-carried meanscomprising; a cyclic device adapted to be initiated by a controlinfluence transmitted from the trackway which will restrict the speed ofthe train it a second control influence is receive-d from the trackwaybefore its cycle of operation has been completed, and which will removesaid'restriction if said cyclic device is again initiated but no secondinfluence is received during the second cycle or" operation; andtrackway means comprising pairs of influence transmitting devices spacedto enforce dilferentspeed restrictions, the first trackway device ofeach pair being permanently active whereby said first trackway devicewill act to remove such speed restriction under clear trafic conditionsahead.

2. An automatic train control system comprising, pairs of influencetransmitting devices located along the trackway and spaced to correspondto predetermined speed limits to be enforced and in which one device ofeach pair is permanently active, and and car-carried apparatus includinga cyclic device which will enforce a speed limit corresponding to thespacing of each active pair of trackway devices and remove previousrestrictions in the movement of the vehicle upon passing a pair oftrackway devices of which only one is active.

3. In an automatic train control system, the combination of pairs oftrackway devices along the trackway, the first of which is permanentlyactive, and of car-carried apparatus adapted to cooperate therewith toset up a predetermined speed restriction when passing a pair of trackwaydevices dependent upon the spacing of these devices and to remove anyrestriction previously enforced when passing over the first device of afollowing pair of trackway devices.

4. An automatic speed control system for railways comprising, a brakecontrol device, and means partly on the vehicle and partly along thetrack for actuating said brake control device if a predetermineddistance along the trackway is traversed in less than a predetern'iinedinterval of time and for restoring said brake control device to normalif more than a certain other predetermined period or" time is consumedwhile traversing a following predetermined distance.

5. In an automatic speed control system for railways, the combinationor" a car-carried apparatus which if actuated applies the brakes of arailway vehicle automatically and means partly on the vehicle and partlyalong the track for actuating said apparatus it a predetermined distanceat a control point is traversed in less than a predetermined time undercaution tratlic conditions and for restoring said apparatus to normalwhen a following control point is passed under clear trafiic conditions.

6. In an automatic speed control system for railways, the combination ofcar-carried apparatus including a device for applying the brakes of avehicle automatically when actuated means for actuating said device iftwo successive control influences are received in less than apredetermined time and for restoring said device to normal it only onecontrol influence is received in said period of time, influencetransmitting devices located in pairs at control points along thetrackway spaced to enforce a predetermined speed limit at each controlpoint, and means for automatically controlling one device of each pairin accordance with traffic conditions ahead.

7. An automatic speed control system for railways comprising, means onthe vehicle for applying the brakes, means for actuating said brakecontrol means it two successive control influences are received from thetrackway in less than a predetermined time and for automaticallyrestoring it to normal it a single control influence is received in asimilar predetermined interval of time, and devices along the trackwayfor transmitting the desired control influences dependent on traflicconditions ahead each including an unmagnetized mass of iron.

8. Car-carried apparatus for train control systems comprising, a traincontrol device of the stick type, means for deenergizing said device iftwo successivecontrol influences arereceived in less than apredetermined interval of time and for again energizing said device itonly: one controlling influenceis received insaid interval of time.

.9. Gar-carried apparatus for speed-control systems for railwayscomprising, a brake control device having a stick circuit and a pickupcircuit, and-means tor-opening-hoth of said circuits momentarily andthen again 7 closing the stick circuit at one point. when two successivecontrol influencesare received in less than a predetermined time and'formomentarily closing both of said circuits and'then maintaining the stickcircuit closed at said point when only one control influence is receivedin said interval of time.

10. In a train control system, the combination of car-carried apparatusincluding a cyclic device, and means for restricting the movement of thetrain it two successive control influences are received during the timenecessary to complete the cycle of said device and for removing previousrestrictions if only one control influence is received during the timeof such cycle; and trackway means comprising pairs of influencetransmitting devices of which one device of each pair-is permanentlyactive and the other is active or inactive dependent on traflicconditions ahead, whereby a pair of active elements is adapted torestrict the movement of the train and a single active element of a pairmay remove such restriction.

11. An automatic train control system comprising, pairs of influencecommunicating trackway devices located in the same path along thetrackway of which one device of each pair is always active and the otherdevice is active at times only and is controlled in accordance withtraffic conditions ahead, and car-carried apparatus which if actuatedrestricts the movement of the train and which is actuated if a controlpoint is passed at which both devices of the pair are active and whichis restored to normal it the train passes a control point at which onlyone device is active.

12. In a train control system, the combination of car-carried meanscomprising, a cyclic device adapted to be initiated by a controlinfluence transmitted from the trackway which will restrict the movementof the train it a secand control influence is received from the trackwaybefore its cycle of operation has been completed, and which will removesuch restriction if said cyclic device is again initiated but no secondinfluence is received during the second cycle of operation; and trackwaymeans comprising pairs of influence transmitting devices of which onetrackwa-y device of each pair is permanently active and, the other iscontrolled in f accordance with traflic conditions ahead,' whereby ifatrain ptL$SBS2MPfilTvOZE tr'ackway devices ctr-which both devices areactive the movement of thetrain isrestricted .13.? In an automatic traincontrol system,

the combination of car-carried apparatus comprising, 1 a.rotatahle,device,- means for restricting the movement of the trainiftwosuccessive "control. influences are received from, the. trackway byuasuitable influence receiving device {on thetrain during a, predetermned; deg-react rotationof said' devlce and, for removing suchrestriction in" the movement of the train it only one control influenceis received during a similar degree of rotation; and trackway meanscompris- 1ng pairs of influence transmitting devices for transmittingcontrol influences magnetically through an intervening air-gap of whichone device of each pair is permanently active and the other device iscontrolled in accordance with traflic conditions ahead, whereby it atrain passes a pair of trackway devices of which both devices are activethe movement of the train is restricted and if it thereafter passes apairv of trackway devices of which the permanently active device only isactive the restriction in the movement of the train is removed.

14. Car-carried apparatus for automatic train control systemscomprising, a relay adapted to be momentarily deenergized on the passageof the car over a suitable active trackway device which trackway deviceis adapted to cooperate with suitable influence receiving means on thecarconnected. to such relay, a normally energized stick device which ifdeenergized restricts the movement of the train said device'having'apick-up circuit and a stick circuit, a normally inactive rotatabledevice having a contact associated therewith which is normally closedand which is open during a predetermined degree of rotation of saiddevice which rotatable device is started from rest if said relay ismomentarily deenergized and which contact is contained in the pick upcircuit of said stick device, and make-before-break contact associatedwith said relay having its normally closed front contact in said stickcircuit and having its back contact in said pick-up circuit, whereby thereception of a single control influence picks up said stick device if itis deenergized and the reception of two control influences during lessthan a predetermined degree of rotation of said rotatable devicecausesdeenergization of said stick device.

15. An automatic train control system comprising, an influence receivingelement consisting of a magnetic core having a normally energizedprimary and a secondary coil thereon, a normally energized relayconnected in a stick circuit in series With said secondary coil, anormally energized electro-responsive device which if deenergizedrestrictsthe movement of the train, a rotatable device, means fordeenergizing said electro-responsive device if two control influencesare received during less than a predetermined degree of rotation of saidrotatable device and for restoring said electro-responsive device tonormal if only one control influence-'is'received during such degree ofrotation, and trackway means comprising pairs of successively locatedunmagnetized magnetic bodies for transmitting such control influences byinducing potentials in said secondary coil one magnetic body of eachpair being provided with a Winding closed in a deenergized circuit underclear trafiic conditions ahead so as to render such body incapable ofinducing a Voltage in said secondary coil as a result of themagneto-motive-force lnduced by said primary coil, whereby saidelectro-responsive device is deenergized when the car passes by a pairof active trackway devices signature.

lVINTHROP K. HOWE.

